I ordered the 3D Print at beta-prototypes. I requested a black finish rather than the standard white. The initial impression was good with the rough finish matching many of the crinkle plastics and paints in the car interior. The holder is also remarkably strong. The material used is PA2200 which is a type of nylon. It looks to me like the black finished is applied on the finished part probably by spray painting.
I took some measurements of the broken holder using calipers and sketching the result on paper. To produce the data for 3D printing I then made a model using Autodesk Fusion. You can obtain a free version for non-commercial use. I produced a STL file from this model.
I have an old English car, nearly 40 for years old as it happens. While many parts are available new from specialist suppliers, some things are impossible to get hold of. The costs of remaking the tooling is just prohibitive for the small quantities likely to sell.
There is a nice system to fix the seatbelts in the car when they are not being used. I think this makes the car look neater when its parked and also is practical. The holder is part number ZKC1550 according to the parts catalogue. The holder is made up of a spring, a backplate and a plastic molding.
